Applying magnetic field

GROMACS version: 2018
GROMACS modification: Yes with plumed
Dear all,
I want to ask that is there a way I can apply magnetic field in my simulation. I have a box of water and magnetic particle (Fe) arranged in a random manner. I want to see how the interaction changes between them when a magnetic field of certain strength is applied to them. Is there anyway to do this in gromacs. If anybody wants to know which equation I am using for the magnetic field I can give them.

Thank you,